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THE first birds probably jumped into the air to start flying. Because the early birds had weak wing muscles, biologists assumed they must have glided out of trees, jumped off cliffs or run along on the ground flapping their wings to create lift. But Kay Earls of the American Museum of Natural History in New York studied how two modern birds take off. Although the starling (Sturnis vulgaris) and the quail (Coturnix coturnix) have different jumping techniques, both birds produced 80 to 90 per cent of their take-off velocity from their legs (Journal of Experimental Biology, vol 203,